Here's a picture I have found on flickr, taken in an outdoor museum in South Korea. I can only recognize the 1st, 3rd and 4th characters: 寶X山房. 寶 is probably not the variant written on the wooden board, but it's the same character. What is the 2nd character?
The original high resolution image is here.
EDIT： My best guess is 丁, but why this odd curvy shape when the rest of the characters are rendered fairly standard?